Dual-boot Windows 7 with Vista

I created a W:\ partition, which is 30GB, and is the place for me to install Windows 7.

I boot via USB stick. Goes fine, I select partition etc. Then I reboot, and then it finishes the last stuff, and then reboots again, where it prepares the computer for the first time, running Windows 7.

Goes well, I come to the screen where it says: "Welcome", but a few seconds later it says: "Shutting down." - and reboots, and then comes to a screen where it says "Verifying DMI pool data..." and doesn't do anything more. Just sits there.
No choice to select the Vista even. Just goes straight to that message.

Now, I've tried to install it again, and booted into Vista, and still need to go into Windows 7, where it gotta finish the installation, but the same thing happens. I'm sure. I tried 3 times.

Any solution, anybody?

By the way, computer specials:

Need more information? Please say so.

Exactly what I did:

Code:

Made partition on 30GB and assigned the letter W:\.
Transferred the Windows 7, to my USB stick, and made it bootable.
Rebooted the computer, and booted from the USB stick.
Came to the Windows 7 install screen.
Installed the Windows 7 on partition W:\.
It rebooted automaticly, and then went to where I can choose wether to go on Vista or Windows 7(There was 2 Windows 7 listed, but went same place).
I chose Windows 7.
It made the final installment.
Rebooted.
I chose Windows 7, again.
It said, that it was preparing the computer for the first time running this OS or something along those lines.
Made something.
The screen: "Welcome" came up.
A few seconds after, this message came up: "Shutting down..."
It rebooted.
Went to "Verifying DMI Pool data", where it hang.
There was no, Vista or Windows 7 list anymore.